The present invention relates to a worked or built nozzle ring for a gas turbine, as well as to a manufacturing method for a worked nozzle ring of a gas turbine. More specifically, the present invention relates to a nozzle ring for an aircraft engine which includes at least one shroud and at least one blade sheet.
Nozzle rings are integral components that in general comprise an annular external shroud, a multiplicity of blade sheets and, if necessary, an annular internal shroud. Nozzle rings are used for example in high-pressure or low-pressure compressors of aircraft engines.
In a conventional manufacturing method, one-piece turbine blades, consisting of a blade sheet and an external platform are first manufactured by forging, casting or an ECM (electrochemical machining) process. Subsequently, in general, four to six such turbine blades are soldered together to form segments. In such a method, the comparatively high manufacturing costs are disadvantageous.
The object of the present invention is to create a manufacturing method for a nozzle ring of a gas turbine of the type specified above that can be executed as simply and as economically as possible. In addition, a nozzle ring that is economical to manufacture is to be created.
The solution of the object relating to the manufacturing method is inventively characterized by the steps: formation of at least one profiled opening in the shroud by means of beam cutting, formation of the blade sheet with at least one two-dimensionally profiled connecting region arranged at the frontal side, insertion of the connecting region into the profiled opening, and connection of the blade sheet with the shroud.
It is preferred that the blade sheet be two-dimensionally profiled, or, respectively, that it be fashioned in prismatic fashion over its entire length, whereby the blade sheet is thereby usefully manufactured by means of extrusion.
As an alternative, it can be advantageous for one sheet surface of the blade sheet to be fashioned in three-dimensionally profiled fashion.
It is highly preferable for the profiled opening in the shroud to be fashioned by means of (high-pressure) laser beam cutting, since with this method, in contrast for example to stamping, openings can be produced with reproducible geometries, without deformation of the adjoining boundary zones. After the laser beam cutting, it can be necessary for the beam exit side to require removal of burrs. With laser beam cutting, the relatively small radii of approximately 0.1 mm to 0.2 mm at the entry and exit sides of the profiled opening can be manufactured. It has turned out that the stamping of the profiled openings is not suitable or, respectively, possible due to the large ratio of the wall thickness of the shroud, approximately 2 mm to 3 mm, to the radii at the entry and exit sides of the openings.
Alternatively, it can be advantageous to fashion the profiled opening using water jet cutting, since with this method as well, or, respectively, with water-jet-guided laser beam cutting, the formation of the relatively small radii of approximately 0.1 mm to 0.2 mm is possible at the entry and exit sides of the profiled opening.
It is also preferable for the connection of the blade sheet and the shroud to take place by means of high-temperature soldering, whereby for the improvement of the soldering quality it is advantageous for the shroud to be nickel-plated chemically or galvanically after the formation of the profiled opening, and/or for the connecting region of the blade sheet to be nickel-plated.
For example for use in high-pressure compressors of aircraft engines, the blade sheet and/or the shroud can preferably be made of a nickel-based alloy. The method can preferably also be applied with materials such as Fe or Ti alloys, or TiAl.
In alternative applications, e.g., for preliminary designing in test benches, it can be useful for the blade sheet and/or the shroud to be made of plastic, whereby the connection of the blade sheet with the shroud then preferably takes place by means of gluing or the like.
In a preferred embodiment, the shroud is an external shroud that is fashioned with a U shape.
The method can also comprise the additional steps: provision of a support plate on the side surface of the shroud facing away from the blade sheet, fashioning of a profiled opening in the support plate that is aligned with the profiled opening in the shroud, insertion of the connecting regionxe2x80x94protruding beyond the above-cited side surfacexe2x80x94of the blade sheet into the profiled opening of the support plate, and connection of the connecting region of the blade sheet with the support plate, as well as connection of the support plate with the shroud. By means of such a supporting of the blade sheet in the region of the shroud, the vibrostability of a worked turbine blade can be increased, and can reach that of a conventionally manufactured turbine blade. The profiled opening in the support plate can be fashioned for example by means of stamping or laser beam cutting. The connection of the support plate with the shroud can preferably take place by means of high-temperature soldering, whereby in such a case the support plate can likewise be nickel-plated in order to improve the soldering quality.
In a preferred construction, the blade sheet is fashioned with two two-dimensional connecting regions arranged on the frontal sides of opposite-lying ends, which connecting regions are connected with an external shroud and, in addition, with an internal shroud. The blade sheet is thereby respectively profiled two-dimensionally at the frontal side for connection with the external and internal shroud, and can be profiled two- or three-dimensionally in the region of the sheet surface. Preferably, a honeycomb sealing or, respectively, honeycomb is applied to a side surface of the internal shroud and joined by means of HT soldering.
Preferably, a multiplicity of blade sheets are provided, whereby the method is then concluded with the step: segmenting of the worked nozzle ring by means of abrasive cutting, a wire EDM electrical discharge machining process, or the like. In such a construction, the shroud is of annular construction, and comprises a number of profiled openings corresponding to the number of blade sheets, which openings are subsequently separated to form segments with e.g. four or six blade sheets.
The part of the solution relating to the worked nozzle ring is inventively characterized in that the blade sheet comprises, at the frontal side, at least one two-dimensionally profiled connecting region that is placed into a profiled opening fashioned in the shroud by means of beam cutting and is fastened thereto or, respectively, connected therewith.
In a preferred construction, the profiled opening is fashioned in the shroud by means of laser beam cutting, since in this way the comparatively small radii of approximately 0.1 mm to 0.2 mm at the entry and exit side of the profiled opening can be reproduced, and can be fashioned without deformation of the adjoining edge regions.
Preferably, the blade sheet is connected with the shroud by means of high-temperature soldering, whereby it is advantageous that the shroud and/or the connecting region of the blade sheet be nickel-coated.
It is highly preferable that the blade sheet comprise, at two opposite-lying ends, two-dimensionally profiled connecting regions fashioned at the frontal side, said regions being connected with an external shroud and in addition with an internal shroud.
In an embodiment, the present invention provides a method of manufacturing a worked nozzle ring for a gas turbine. The nozzle ring includes at least one shroud and at least one blade sheet. The method comprises the steps of beam cutting at least one profiled opening in the shroud, forming the blade sheet with at least one two-dimensionally profiled connecting region arranged on a front side of the blade sheet, inserting the connecting region of the blade sheet into the profiled opening of the shroud and connecting the blade sheet to the shroud.
In an embodiment, the length of the blade sheet is two-dimensional.
In an embodiment, the blade sheet comprises a sheet surface which is three-dimensional.
In an embodiment, the step of forming the blade sheet comprises milling.
In an embodiment, the step of forming the blade sheet comprises profile grinding.
In an embodiment, the step of beam cutting is further characterized as high-pressure laser beam cutting.
In an embodiment, the step of beam cutting is further characterized as water-jet cutting.
In an embodiment, the method further includes the step of nickel-plating the shroud.
In an embodiment, the step of forming the blade sheet further comprises nickel-plating the blade sheet.
In an embodiment, the step of connecting the blade sheet to the shroud comprises high-temperature soldering.
In an embodiment, the blade sheet and/or the shroud are fabricated from a material consisting of nickel, titanium, a nickel-based alloy, a titanium alloy and plastic.
In an embodiment, the step of connecting the blade sheet to the shroud includes gluing the blade sheet to the shroud.
In an embodiment, the shroud is an external shroud.
In an embodiment, the shroud is connected to a support plate and a profiled opening is formed in the support plate that is in alignment with the profiled opening in the shroud and the inserting step further comprises inserting the connecting region of the blade sheet through both the profiled opening of the shroud and the profiled opening of the support plate and the connecting step further comprises connecting the blade sheet to the shroud and the support plate.
In an embodiment, the nozzle further includes an inner shroud and an outer shroud and the beam cutting step further comprises beam cutting profiled openings in both the inner and outer shroud and the step of forming the blade sheet comprises forming two-dimensionally profiled connecting regions disposed at opposing ends of the blade sheet and the inserting step further comprises inserting each connecting region of the blade sheet into the profiled opening of one of the inner and outer shrouds and the connecting step further comprises connecting the blade sheet to both the inner and outer shrouds.
In an embodiment, a plurality of blade sheets are utilized and the method further includes the step of segmenting the nozzle ring with a process selected from the group consisting of abrasive cutting and wire EDM.
In an embodiment, the present invention provides a nozzle ring as described above.
Other objects and advantages of the invention will become apparent upon reading the following detailed description and appended claims, and upon reference to the accompanying drawings.